I recently done a truck based on a mike hill tutorial http://www.mikehill.design/
It was a fun and new experience to me. I've learned a ton of new stuff. Now I am less afraid of 3D and for sure will use this approach for next designs.
1. Simple sketches to get the idea out.
2. 3D design and model
3. Lineart to show the design
After doing the lineart by hand I found that you can do awesome base by rendering the model in keyshot in just a couple of minutes. It sure need some polishing but as a base works great. Here is a comparison :
4. Color versions and render